Steam-actuated valve.



PATENTED SEPT. 11, 1906.

E. E. THOMAS. STEAM ACTUATBD VALVE.

APPLICATION FILED 0GT.12. 1905.

4 SHEETS-SHEET 1.

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PATENTED SEPT. 11

E. B; THOMAS. \STEAM AGTUATED VALVE.

APPLICATION FILED 0013.12.1905.

4 SHEETS-SHEET 2.

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EDWIN E. THOMAS, OF PORTLAND, OREGON.

STEAM-ACTUATED VALVE.

Specification of Letters Yatent.

Patented Sept. 11, 1906.

Application filed October 12,1905. Serial No. 282,385-

To at whom it may concern:

Be it known that I, EDWIN E. THOMAS, of Portland, Multnomah county, Oregon, have invented certain new and useful Improve ments in Steam-Actuated Valves, of which the following is a specification.

My invention relates to engines designed particularly for operating drag-saws used in cutting logs for shingles, wood for fuel, bridge-timbers, and generally around timber and logging camps, and is also adapted for use with vertical sawing-machines, drills, &c. Heretofore it has been customary in engines used for this purpose to operate the valve by means of a mechanism carried by the crosshead or piston, which when near the end of its stroke will engage some appliance attached to the valve. Such valve-operating means has been found unsatisfactory, as it is practically impossible to keep the operating parts properly lubricated, and when the machines are handled by inexperienced persons, as frequently is the case, thewear of such parts is very rapid and soon leads to a condition that renders the machine unsuited for the purpose designed. Furthermore, in machines of the ordinary type there is no way of regulating the speed except by the movement of the operators valve, and in the hands of an inexperienced or careless operator this has been found to be a very undesirable arrangement, often resulting, through the toorapid or extreme opening of the valve, in seri ous damage to the machine or its parts.

The object, therefore, of my invention is to provide an engine of extremely simple construction having a minimum number of working parts and joints which are easily kept in proper adjustment and are comparatively inexpensive to manufacture and keep in repair.

A further object is to provide an engine which an unskilled person may operate without danger of dan'iaging the machine; and a still further object is to provide an engine and valve which, though primarily designed for use with a drag-saw, is also adapted for a variety of other purposes.

My invention consists generally in an engine having a piston and a floating or loose valve operated by the fluid-pressure which moves the piston and without the employment of any mechanical appliance whatever between the valve and piston.

Further, the invention consists in providing means for regulating the speed of the engine through the travel of the main floating valve, such control being involuntary on the part of the operator and governed by the speed of the engine rather than by the movement of the stop or operators valve.

Further, my invention consists in providing means whereby the )iston and valve will be cushioned by the flui -pressure when near the limit of their movement in each direction to prevent them from striking the ends of the cylinder or valve casing.

Further, the invention consists in providing means for equalizing the pressure on the ends of the valve to cause it to remain at rest during the time the piston is traveling nearly the length of the stroke in the cylinder.

In the accompanying drawings, forming part of this specification, Figure 1 is a side elevation of a drag-saw engine embodying my invention, showing the engine attached to a saw and in use. Fig. 2 is a plan view of the engine and cross-head. Fig. 3 is a longitudinal vertical section through the engine cylinder and valve which controls the movement of the saw. illustrating the piston and valve in proper position for starting the engine. Fig. 5 is a Fig. 4 is a similar view,

detail sectional view showing the position of the piston and valve after they have begun their movement toward the cross-head end of the cylinder. Fig. 6 is a detail sectional yiew illustrating the position of the balancing or equalizing ports in the valve-casing. Fig. 7 is a vertical transverse section on the line :1: :1; of Fig. 3. tical section on the line i; e of Fig. 3. Fig. 9 is a horizontal section on the line w w of Fig. 8. Fig. 10 is a vertical section on the line y y of Fig. 3. Fig. 11 is a transverse vertical section on the line 2 z of Fig. 3.

In the drawings, 2 represents the cylinder of the engine; 3, a hollow piston having a hollow rod 4 secured to a cross-head 5.

6 is a steam-pipe, also secured at one end Fig. 8 is a transverse verto the cross-head and extended through a stufling-box 7 into the main steam-pipe 8,

within which it is adapted to telescope or through said valve and having closed ends and providedwith ports 14 and 17, communicating with annular ports 15 and. 16, provided.

in said valve and leading to-the outside of the same. Buffer-plates 18 and 19 are mounted on the ends of said stem and contact with rior of the valve-stem to-the steam-chest 22.

Stufling-boxes are provided to prevent the escape of steamfromthe steam-chest and valve-casing.

2:6 is an exhaust-port in the valve-casing, and. 27. an. annularv exhaust cavity or. chamber. provided in the valve near its middle and" communicating at. all-points in the travel. of the valve with said exhaust-port.

2.8 and 29 are ports in the ends-of the valve 12.,throughwhichlive steam enters from the steampassages or. ducts 30 and 31 to operate thevalve, and 32 and 33 are passages through which live steam passes from the. valve to 0perate the piston.

34, 35 36, and 37 are ports extending through the valve-casing and communicat.- ing, .res pectively, with the passages 30,- 32, 33, and. 31....

, 38. andi 38- are longitudinal grooves provided. on the inner-surface of the cylinder near. each. end, and 1 39 represents ports providedinthe walls of. the hollow. piston3 and adapted" to register, with. the grooves38 and 38" when the piston isnear: the limit. of its stroke. ineachdirection 40, (see Figs..1and.2,) isaby-pass pipe provided' with a. stop-valve .41. andlleading. from the couplinglO. in the main steam-pipe 8 to the steam chest 22, the valve 41 allowing the attendant to. regulate the supply of steam admitted. to the valve-stem 13 for operating the'pi'sten.3.

42. and 43-, are steam-passages connecting.

the-eXhaust-chamber 27 with the spaces betweenthe ends of. the valve-casing andthe slide-valve 12,. one of said spaces being.- indicated by numeral. 45,,the connection of the spaces at the ends of the valve-casing with saidpassages being made alternately asthe valve is movedandthe piston reversed.

The operation of the-engine is asfollows: Assuming, the pistonand slide-valve to hem the position indicated inFig. 4, steam is admitted tio the pipe 8, from whence itwill'flow throughthe pipe 6 and port 9 into the hollow rod. 4 and piston 3. i

- then. opened. a suitable distance and. the

steam. allowed. to flow throughthe' pipe into the steam-chest and from thence into the hollow stem l'3an'dthroughthe portsal4, 15,.and 361 to the steam-passage 33 and to the cylinder in the rearof the piston. piston will. immediately be driven forward,

The stop-valve 41. is-

The-

tween it and theend of the cylinder and prevent it from striking said end and being damaged by the shock or causing injury to the other parts of the engine. The steam-cushion will stop further movement of and reverse the piston, and the steam flowing down through the passage 30 and the port 34 will entertheport: 28-and pass intoithe space betweenthe endof the valve anditscasing, whereupon the valve willbe moved immediately to the position indicated in Fig. 3, and the steam will flow from the stem-13 through the ports 16 and 35 intothe steam-passage 32 and openthe rear of the piston to the exhaust. flowing through the hollow piston and the ports 39- into the grooves 38 and the end of the cylinder and driving. the piston toward the opposite or cross-head end of the cylinder. As soon as-thepiston has-moved a sufficient distance to cut off the ports 39 from communication with the grooves 38'the passage 32 will be uncovered, and the steam flowing therefrom into the end of the cylinder willdrive the piston to the other end. As soonas the pistonreachessaid other end of the cylinder the=ports- 39 will communicate with the grooves 38, and steam will flow from the interior. of the pist'oninto the stufling-box or cross-head end of the cylinder and form a cushion for the piston at. that. end, reversing its direction of movement, as describedwith reference to the other end ot the During this time the steam'has been cylinder. At the same timethe steam will flow down through the-passage 31 and the ports 37 andi'29 into-the space between the end of. the valve 12 and its casing and move the said valve back. tothe positionshown in Fig. 4. The ports 42 and 43 serve to=equalizethe pressure of the exhaust on-the valve l2.and1hold it at' rest or stationary during'the intermediate movement of the piston. For instance, suppose the piston and valve to be in the position indicated in. Fig. 3. The space at the'right hand or in the rear of the piston will be on the exhaust through the passage 33, the chamber. 27-, and the port 26. The passage 31 is also connected with the cylinder and with the space betweenthe end of the valve and the head of the casing through. the ports 37"and 29, and the entrance of the exhaust into this space would tend to move the valve prematurely; but themove the valve into position to admit steam to the passage 33 of the cylinder for the next stroke of the piston. When the valve 12 is in the opposite end of its casing from that shown, the port 43 serves to equalize the exhaust-pressure on the ends of the valve. The ports 42 and 43 also serve to regulate the speed of the engine by means of the pressure delivered through the stop-valve. WVhen this valve has been opened to a point that will cause the operation of the engine at its maximum speed with a given boiler-pressure, any further opening of the stop-valve will automatically reduce the distance of the travel of the main or floating valve, thereby cutting down the port-openings and the supply of pressure .to the cylinder and maintaining the engine at a practically constant speed. With this arrangement it will be impossible for an inexperienced or careless operator to wreck or damage the engine through the too rapid or extreme opening of the stop-valve. The control is positive and instantaneous. If the operator opens the valve wider than is necessary to supply the proper pressure to the piston and valve, the movement of the valve will be lessened and the port-openings correspondingly reduced to compensate for the overplus of pressure admitted to the valve.

In building the engine the ports will be properly proportioned according to the de sired speed of the engine. In this engine it willbe noted that the fluid-pressure flowing through ahead of the piston at each end of the cylinder will act as a cushion at that. point and reverse the movement of the piston and the pressure will flow from the cylinder down into the valve-casing between its end and the valve and move the valve to the opposite end of the casing. This movement will uncover the passage leading to the cylinder, through which pressure will pass to drive the piston to the other end of the cylinder, where the operation described will be repeated. When the pressure is being admitted at one end of the cylinder and the other end is on the exhaust, the equalizing-ports will cause the valve to be balanced and remain stationary while the piston is traveling from one end of the cylinder to the other. If there is any excessive pressure, due to the too-wide opening of the stop-valve, it will flow through the balance-ports ahead of the valve and limit its travel and prevent the full opening of the ports leading to the cylinder. 1 am thus able to provide an engine which does not require a skilled or experienced person to operate it. The valve is operated entirely by the pressure and neither the piston nor the valve have any moving parts to come in contact with one another and liable to be broken or disarranged. The engine is automatically governed, the ports being partially choked and the area of the passage cut down whenever the stop-valve is opened to deliver more than enough steam to run the engine at its normal speed. A uniform maximum speed for the engine under all conditions is thus insured.

I have shown and described this engine operated by steam-pressure; but it will be understood that any other elastic-lluid piessure, such as air, may be employed with equally good results.

I claim as my invention 1. The combination, with a cylinder having a piston and two passages leading into each end, of a loose or floating valve having ports communicating respectively with said passages, means for delivering a fluid-pressure to the piston and to said valve and means whereby the pressure delivered to said, piston will, when the piston is near the end of its stroke, be conducted ahead of the piston and admitted through one of saidpassages to said valve to operate it and open the other cylinder-passage at the same end for the admission of fluid-pressure to the cylinder, substantially as described.

2. The combination with a cylinder and its piston having a plurality of passages leading into its ends, of a floating valve having an exhaust-port, and ports communicating respectively with a passage from one end of said cylinder and with a pressure-supply to conduct it into the other end of said cylinder when said piston is near said other end, and said valve being moved by the pressure flowing through said passage from said cylinder to open said one end of said cylinder to the pressure-supply and the said other end to said exhaust, substantially as described.

3. The combination with a cylinder and piston provided with means for delivering fluid-pressure in front of said piston as it approaches the ends of said cylinder, of a slidevalve having a casing and ports communieating alternately with the ends oi said cylinder as said piston approaches said ends and with the space between the ends of said casing and said valve, and said valve-casing having ports communicating alternately with the ends of said. cylinder and with the pressure-supply, and said last-named ports being normally closed during the initial movement of said valve and open during its final movement, substantially as described.

4. The combination with a cylinder having grooves in its inner surface near each end, of a piston having ports adapted to register with said grooves when said piston is near the end of its stroke in each direction, a hollow piston-rod communicating with said ports and with a fluid-pressure supply, a valve-casing, passages provided in said cylinder and communicating with the ports in said casing and. with the ends of said cylinder, and a slide-valve in said casing having ports communicating with said passages and with the space between the ends of said casing and said valve, substantially as described.

5 The combination with a cylinder provided with interiorly-arranged passages near each end, of :a piston having'p'or-ts to register with :said passages when said piston is near the end of its stroke in each direction, a hollow piston-rod communicating with said ports, a fluid-pressure supplycommunicating with said rod, a va'lvecasing having ports, passages leading ir-om said ports to the ends of said cylinder, a slide-valve having ports communicating with said passages, a hollow stem tor said valve ports communieating with said valveports, a chest communicating with the interior oi said stem, and a by-pass pipe having a valve leading from said fluid-pressure supply to said chest, substan-tially as described.

-6. The combination a cylinder having inteiiorly-arranged passages near each end, of a piston having ports to register with said passages when near the limit of its stroke in each direction, a hollow piston-rod communicating with said ports and with a *fluidpressure supply, a valve-casing having an ex haus't-por-t, passages 30, 32, 33 and 31 communicating with the interior of said valve casing and with the ends of said cylinder, a slide-valve provided in said casing and having an exhaust-chamber communicating with saideXhaust-port, and ports '28 and 29 communica'ting alternately as the valve is moved with the passages 39 and 31 and the spaces between the ends of said valve and the ends of-said easing, said valve also having ports 15 and 16ficommuni cating alternately with said passages and 32, and means connecting said ports 15 and 1 6 with the fluid-pressure supply, substantially as described.

7 The combination with a cylinder and piston having means for delivering a fluidpressure in front of said piston as it approaches the ends of saidnylinder, said cylinder having passages 30, 31, 32 and 33 leading into its ends, a valve-casing communicating said passages '30, 31, 32 and '33 and having an exhaust-port, a slide-valve provided in said casing having ports 28 and 29 communicating alternately with said passages 30 and and with the ends oi said casing whereby when said piston-ports register with the passages in said cylinder fluid-pressure will pass through said passages 30 and 31 to operate said valve, and said valve having ports 15 and 16 communicating alternately with said passages 32 and '33 and connected with a fluid-pressure supply, substantially as described.

'8. The-combination with a cylinder and its piston, of a loose or floating valve having ports communicating with the ends of said cylinder and whereby the approach of said piston to the limit of its stroke in either 'direction will admit pressure to said valve to operate it also, and means for equalizing the pressure on said. valve during the intermediate movement of said piston.

9. The combination with a cylinder and piston provided with means for delivering fluid-pressure in front of said piston as it :approaches the ends of said cylinder, of a slidevalve having a casing and ports communicating with the ends of said cylinder and with the space between the ends of said casing and said valve, and said valve having also an exhaust-chamber and ports communicating valve having an exhanst-chambercommnnieating with said port, and ports 28 and 29 communicating alternately with the space between the ends of said valve and said "casing and with said passages 30 and 31, said valve also having ports 15 and 16 communicating with a fluid-pressure and alternately with said passages 33 and 32, and ports 42 and 43 oo1nmnnicatmg respectively with said exhaust-chamber and with the ends of said casing, substantially as described.

11. The combination with a cylinder and piston having means for "delivering a fluidpressure to the ends of said cylinder, of a slide-valve having ports communicating with the ends of said "cylinder and operated by the pressure therefrom, means having a stop valve for delivering fluidpressnre to said slide-valve tor said cylinder, and means whereby an excess of pressure delivered by said stop-valve will lessen the travel of said slide-valve andcu't'off the supply of pressure to said cylinder, substantially as described.

12. The combination with a cylinder and pistonprovided with means for delivering fluid-pressure in front of said piston as it approaches the ends of said cylinder, of a valve having a casing, and ports communicating with the ends of said cylinder and with the space between the'ends of said casing and said valve, and said valve having also :anexhaustchamber and ports communicating with the ends of said cylinder and with the pressuresupply, a stop-valve for controlling the admission of pressure to said valve, and ports connecting the ends of said valve-casing with said exhaust-chamber whereby when said stop-valve is opened too quicldy or too iar the excess pressure will flow ahead of said valve and lessen the travel of the same, substantially as described and for the purpose specified. I i

1 3. The combination with a cylinder-having fluid-pressure passages near one end, of a piston having ports to register with said passages when said piston is near the end of its stroke, and a hollow piston-rod communicating with said ports and with a fluid-pressure supply whereby a cushion will be formed between the piston and the cylinder-head, for the purpose specified.

14. The combination with a cylinder having grooves in its inner surface near each end, of a piston having ports to register with said grooves when said piston is near the end of its stroke in each direction, and a hollow piston-rod communicating with said ports and with a fluid-pressure supply whereby a cushion will be formed in each end of the cylinder between its heads and the approaching piston, substantially as described.

15. The combination with a cylinder and piston provided with means for delivering fluid-pressure in front of said piston as it approaches the ends of said cylinder, of a sliding valve having a plurality of ports at each end communicating with a corresponding number of passages leading to the ends of said cylinder and said valve having pressure-supply and exhaust ports, and one of said valveports in each end communicating with a space provided at the ends of said valve and the other valve-ports communicating alternately with the pressure-supply and exhaust .ports whereby when fluid-pressure is admitted to one end of said cylinder in the rear of its piston and said piston moves to the opposite end of the cylinder, fluid-pressure will enter the space at one end of said valve and operate it to cut off the fluid-pressure to said one end of the cylinder and open that end to the exhaust and admit pressure to the other end of the cylinder, substantially as described.

In Witness whereof I have hereunto set my hand this 25th day of September, 1905.

EDWVIN E. THOMAS. Witnesses: I

ELIJAH CORBETT, G. A. HIBBARD. 

